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Aggregates are advancing well.

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This commit is contained in:
David Lebée
2018-03-13 22:16:58 -05:00
parent e4ce956d8a
commit ba702d3e81
2 changed files with 46 additions and 35 deletions
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PoweredSoft.DynamicLinq/Helpers/QueryableHelpers.cs
+37 -17
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@@ -139,26 +139,12 @@ namespace PoweredSoft.DynamicLinq.Helpers
var mi = Expression.MemberInit(ctor, bindings);
var lambda = Expression.Lambda(mi, parameter);
/*
public static IQueryable<TypeTwo> Tester(IQueryable<TypeOne> data)
{
var source = Expression.Parameter(typeof(TypeOne), "source");
var selector = Expression.Lambda<Func<TypeOne, TypeTwo>>(
Expression.MemberInit(Expression.New(typeof(TypeTwo)),
Expression.Bind(typeof(TypeTwo).GetProperty("TwoProp"), Expression.Property(source, "OneProp"))),
source);
return data.Select(selector);
}*/
//public static IQueryable<TResult> Select<TSource, TResult>(this IQueryable<TSource> source, Expression<Func<TSource, TResult>> selector);
var selectExpr = Expression.Call(typeof(Queryable), "Select", new[] { query.ElementType, typeToCreate }, query.Expression, lambda);
var result = query.Provider.CreateQuery(selectExpr);
return result;
}
private static Expression CreateSelectExpression(IQueryable query, ParameterExpression parameter, SelectTypes selectType, string path)
private static Expression CreateSelectExpressionForGrouping(IQueryable query, ParameterExpression parameter, SelectTypes selectType, string path)
{
if (selectType == SelectTypes.Key)
{
@@ -166,22 +152,56 @@ namespace PoweredSoft.DynamicLinq.Helpers
}
else if (selectType == SelectTypes.Count)
{
// TODO: check if we need to ensure if grouped before getting second generic argument.
var notGroupedType = parameter.Type.GenericTypeArguments[1];
var body = Expression.Call(typeof(Enumerable), "Count", new[] { notGroupedType }, parameter);
return body;
}
else if (selectType == SelectTypes.LongCount)
{
// TODO: check if we need to ensure if grouped before getting second generic argument.
var notGroupedType = parameter.Type.GenericTypeArguments[1];
var body = Expression.Call(typeof(Enumerable), "LongCount", new[] { notGroupedType }, parameter);
return body;
}
else if (selectType == SelectTypes.Average)
{
/// https://stackoverflow.com/questions/25482097/call-enumerable-average-via-expression
var notGroupedType = parameter.Type.GenericTypeArguments[1];
var innerParameter = Expression.Parameter(notGroupedType);
var innerMemberExpression = ResolvePathForExpression(innerParameter, path);
var innerMemberLambda = Expression.Lambda(innerMemberExpression, innerParameter);
var body = Expression.Call(typeof(Enumerable), "Average", new[] { notGroupedType }, parameter, innerMemberLambda);
return body;
}
else if (selectType == SelectTypes.Sum)
{
var notGroupedType = parameter.Type.GenericTypeArguments[1];
var innerParameter = Expression.Parameter(notGroupedType);
var innerMemberExpression = ResolvePathForExpression(innerParameter, path);
var innerMemberLambda = Expression.Lambda(innerMemberExpression, innerParameter);
var body = Expression.Call(typeof(Enumerable), "Sum", new[] { notGroupedType }, parameter, innerMemberLambda);
return body;
}
throw new NotSupportedException($"unkown select type {selectType}");
}
private static Expression CreateSelectExpression(IQueryable query, ParameterExpression parameter, SelectTypes selectType, string path)
{
if (!IsGrouping(query))
throw new NotSupportedException("Select without grouping is not supported yet.");
return CreateSelectExpressionForGrouping(query, parameter, selectType, path);
}
private static bool IsGrouping(IQueryable query)
{
// TODO needs to be alot better than this, but it will do for now.
if (query.ElementType.Name.Contains("IGrouping"))
return true;
return false;
}
public static IQueryable GroupBy(IQueryable query, Type type, string path)
{
var parameter = Expression.Parameter(type, "t");